I have a way to get the glass crystal clear and it is cheap and easy. I do not use this method too often as I clean my windows very often now. But when they get real dirty and grimy this works. Use dishwasher liquid. Put a few drops in a bottle of water and mix it well. Place a large towel, like a beach towel, on the dashboard or rear deck, and spray the glass generously. Sometimes I just put the cleaner in a kitchen pot and dip a cleaning cloth in it. Wipe the glass really well while keeping the glass well saturated. Then get yourself a small squeegie and wipe the solution down to the towel. Use a paper towel to dry off where the squeegie missed. Perfectly clean glass. I use this on interior only as the solution will most likely strip wax. Don't dis the idea until you try it.
Don
Don